mls

Hi everyone! I've been having this problem for a while and can't figure it out: I though it might be the short belts so i tightened them put sadly it didn't improve the situation! The bed is also levelled nicely as it always only seems to be an issue on diagonal flat surfaces. Could it be slicer related? Hopefully, someone has some ideas! Regards Max

Hi everyone, I re-soldered everything again and decided to replace the pt100 sensor with one I had bought right at the beginning of all these problems. Everything is perfect now. The ambient temperature reading is correct and I have been printing happily ever since. I'm just glad I didn't give up and buy a new heated bed (as was the advice from igo3d!). Thanks for all the advice and help. Regards, Max

Hi everyone! After re-heating all the solder points on the heated bed a few times, also adding more solder on some parts as i went, everything seems to be stable now. The only thing that has changed is at ambient room temperature (21 degrees) the ultimaker is showing a bed temp of 28 degrees. The resistance of 109.2 Ohms would seem to confirm that but something must of happend whilst soldering. Is there anyway to adjust for the change in resistance in the firmware? I have looked at the PID values but i don't think that is a solution. Regards, Max

Yes they did! It was one of the first things I did to try and correct the problem. Thanks for the tip though!

Hi gr5, Thanks for the info! The resistance of the thermistor always measures 108 Ohms at 21 Degrees which is fine! I also tried the solution proposed by neotko (recompiling the firmware to use temp2 instead of temp3) and i am still getting the same strange behaviour! I have already reheated the connection of the temp sensor to the board but i will do as you suggested and give all the connections a work over! What do you mean by "remove and re-insert the PT100 wiring"? Thank you! Regards, Max

Hi neotko, I don't know how much you know about the firmware but that would mean switching the pin numbers from 10 to -1 wouldn't it? I just looked it up in the firmware and that's the change that would make sense. It would be great if you or someone else could confirm this as there is very little information about what pin numbers correspond to what parts on the board! Hopefully this works! Regards and thank you, Max

Maybe I miss the point but this seems perfectly normal to me.... assuming the ambient temperature of the room is 24 Celsius. Did you check the PT100 separately? I mean just go into maintenance, to heat the bed (so you can read the temperature) leave it to zero and then heat it with an external source like a heardrier? Ofcourse if you have a spare PT100 (like from the hot-end) you can also just stick it to the bed and test like this. That is exactly the problem. When the temperature sensor cable (going to temp3) is unplugged the resistance at all points (at the thermistor, on the block and at the end of the cable) all measure exactly 108 Ohms. This is correct for the 21 degrees i have in the room. Today after trying some other things, like when the cable is attached to the electrical board, I measured 45 Ohms at the thermistor. Today when the ultimaker was switched on the display showed 21 Degrees (somedays it is 35 Degrees/24 Degrees, different every day). However, the resistance measured was 175 Ohms at the thermistor. How can the thermistor be changing its resistance (at a constant room temperature) if it is connected to the electrical board? I wanted to rule the heated bed out by attaching a new pt100 thermistor directly to the board but haven't got round to it yet. Thanks for the help! Max

Thanks for the heads up! I'll probably end up getting an official one. The thing is i'm not sure if mine is broken or not! My issue is in another part of the forum: https://ultimaker.com/en/community/view/18073-another-ultimaker-2-heated-bed-issue Maybe you can give an opinion on the issue! Regards and thanks again! Max

Hi neotko, Thanks for the info. Should have searched it myself though! After reading your comments and those of others there were a few things I looked out for! http://www.aliexpress.com/item-img/3D-printer-accessories-Ultimaker-v2-1-1-control-board-Ultimaker-2-generations-board-finished-board-free/32474543921.html# I think the above link shows a pretty decent replica with power switch soldered on and the plastic (what part?) the right way around! Do you notice anything else wrong with that board other than the quality of certain parts probably being inferior? Regards and thanks again! Max

Hi, Does anyone have any experience buying a new main board from China / Aliexpress? A new board in europe cost around €350! The price from china with customs duty comes to around €150. A lot cheaper! Hopefully someone can share their experience! Regards, Max

Hi, Hopefully someone can clarify this for me. I have recently got the TEMP SENSOR BED error. The first thing I did was check all the connections and leads going to the heated bed and to the motherboard. Everything was fine. I then read about the issues with the soldering of the temp sensor attachment point to the heated bed. Seemed fine but I reheated the solder anyway. After checking everything I got my multimeter out, and with the heated bed completely disconnected from the machine, I measured a resistance of 108 Ohms. Falls perfectly in line with the 21 Degrees ambient temperature I have in the room. Thinking everything was ok with the thermistor I reattached everything and switched the ultimaker back on. Going to the maintenance section where you manually set the temperature for the heated bed, whilst leaving it at 0 Degrees, I noticed the temperature reading was 24 Degrees. Not normal. At this point the ultimaker is still on and the TEMP SENSOR BED error is once again on the screen. I then measured the resistance again and the reading was around 175 Ohms (also not normal). The heated bed is at ambient temperature. Also, if I heat the bed up the temperature shoots past the target temperature and then slowly comes back down. I then went up to 70 Degrees and the (measured) temperature rapidly hit 180 Degrees and then the error occurred again. Reading other posts I have already decided to purchase a new PT100 thermistor. Does this all point to the thermistor being the problem though? Could it be anything else (mainboard)? I have had the printer 1.5 years now and nothing has gone wrong up until this now. Hopefully the solution is as simple as soldering and sticking the new thermistor to the heated bed! Just to recap: with the printer under power, resistance was measured at 175 Ohms (correct?). Without power it measured 108 Ohms. I haven’t measured the output voltage of the heated bed directly from the mainboard yet. Thanks for all the help in advance! Max Update 10.11.2015: I just tried some more things: With the temp sensor cable unplugged I measure 108 Ohms. With the temp sensor cable plugged in I measure 45 Ohms. With the temp sensor cable plugged in and the ultimaker on I measure 175 Ohms. Display temp is 21 Degrees. Is the control board malfunctioning? Regards, Max